Circuit breakers that are designed to break DC are commercially available. These commercial DC circuit breakers are typically designed to handle a maximum power limit at approximately 1.5 kW. Some of these use mechanical components and some are only intended for use in small applications, such as house hold electronics. Another group of commercial DC circuit breakers use explosives to break the circuit, which introduces the need of component replacement and maintenance.
The patent application U.S. Pat. No. 6,738,246 B1 discloses an electrical circuit breaker for protection against small and large over-currents. This invention operates in the voltage range 100V-1 kV. A micro relay switch is used in conjunction with a component for short-circuit current limiting. The micro relay switch is a mechanical switch and switches off small over-currents, and the component for short-circuit current limiting switches off very large over-currents. The use of the component for short-circuit current limiting destroys the micro relay switch.
The patent application WO 2007/022744 A1 discloses a current limiting switch that contains a mechanical switching unit.
WO 2007/020539 provides a current limiter circuit configuration for a battery charging circuit. This circuit configuration rapidly detects and limits any current variation through a gate-controlled switching device. The invention is intended to be used in portable and mobile devices.
DE 199 55 682 A1 discloses a current limiting device for high voltages. This invention uses explosives to open a current path. The use of explosives implies the need to replace components to regain operation of the device, and maintenance of the system. Maintenance takes time and requires spare parts. During maintenance time the system can not fully operate.
US 2005/0002152 A1 discloses a fault current limiting system and method that is based on the use of a combined fast switch and an electrical fuse in parallel. After a fault is detected the fast switch opens in a very short time and transfers the current to the fuse, which is able to blow out, thereby interrupting the short-circuit current. An automatic system takes care of replacing the blown-out fuse set with a new one. An explosive based cartridge can be used instead of a fast switch.
The publication “A DC Circuit Breaker for an Electric Vehicle Battery Pack” by G. Walker discloses a static DC circuit breaker that uses a MOSFET. This solution handles voltages in the range of hundreds of volts.
Examples of other known solutions are DE 4 108 049 which discusses a protection system for AC systems and thus is not suitable for the DC applications. US 2002/0030532 illustrates a solution avoiding failures caused by heat in a semiconductor switch having an IGBT mounted on a circuit board, as is well known in the art. EP 1 811 665 discusses a gate controlled switch and the article by Krstic, S et al; “circuit breaker technology for advanced ship power systems”, Electric ship technologies Symposium 2007, ESTS apos; 07. IEEE 21-23 May 2007, Pages 201-208 which discusses a fast circuit switches based on IGBT and IGCT for use in ships.